Re: [bess] Hub-and-spoke support in EVPN: RFC 8317 vs.draft-wang-bess-evpn-context-label-04

[[e-mail]]

Hi Jeffrey and Sasha,







The flows of E-tree services typically are P2MP conections,


But the flows of hub/spoke services typically are MP2MP connections, 


the spoke PEs can connect to each other under the assistance of the hub PE.


The hub/spoke services is actually a special pattern of VPLS, whose MP2MP nature will be persisted.






So they are very different as what Jeffrey has pointed out.






But the hub/spoke secenario is very similar to the AR REPLICATOR/LEAF, IMHO.


And draft-ietf-bess-evpn-virtual-hub already applied a certain extent of AR REPLICATOR behaviors to the hub PEs.


The only issues remained in draft-ietf-bess-evpn-virtual-hub is that when RRs exists between hub-PE and spoke-PEs.


If the AR REPLICATOR behaviors are removed from that draft,


I think the hub/spoke scenario can't be well supported because that the RRs are widely used.


and the AR REPLICATOR behaviors will still be required even if there are no RRs.


 


And I think the approaches discribed in draft-wang-bess-evpn-context-label-04  can solve the problems caused by RR existence.






Best Regards,


Bob











原始邮件



发件人：Jeffrey(Zhaohui)Zhang <[e-mail]>
收件人：Alexander Vainshtein <[e-mail]>;[e-mail] <[e-mail]>;
抄送人：Michael Gorokhovsky <[e-mail]>;[e-mail] <[e-mail]>;
日 期 ：2020年08月20日 22:46
主 题 ：RE: Hub-and-spoke support in EVPN: RFC 8317 vs.draft-wang-bess-evpn-context-label-04




Hub and spoke EVPN and E-tree are different.


 


However, draft-ietf-bess-evpn-virtual-hub should address the following two at least:


 


   *  MPLS EVPN can't support hub/spoke usecase, where the spoke PEs can


      only connect to each other through the hub PE.  Especially when at


      least two of the spoke PEs are connected to a common route


      reflector.


 


   *  MPLS EVPN can't work as an AR-REPLICATOR.  Because the AR-


      REPLICATOR will apply replication for the ingress AR-LEAF too.


      But a packet shoud not be sent back to the AR-LEAF where it is


      received from.


 


Jeffrey


 


 


Juniper Business Use Only



From: BESS <[e-mail]> On Behalf Of Alexander Vainshtein
Sent: Thursday, August 20, 2020 9:36 AM
To: [e-mail]
Cc: Michael Gorokhovsky <[e-mail]>; [e-mail]
Subject: [bess] Hub-and-spoke support in EVPN: RFC 8317 vs. draft-wang-bess-evpn-context-label-04




 


[External Email. Be cautious of content]


 


Dear authors of draft-wang-bess-evpn-context-label-04,


 


Section 2 “Problem Statement” of draft-wang-bess-evpn-context-label-04 states that “MPLS EVPN can't support hub/spoke use case, where the spoke PEs can only connect to each other through the hub PE.  Especially when at least two of the spoke PEs are connected to a common route reflector”.


 


I have to admit that I do not understand why support of the generic E-Tree functionality in EVPN defined inRFC 8317 is not sufficient for handling this use case.


 


In particular I do not see why connection of Spoke PEs to a common RR affects the EVPN behavior (or L3vPN Hub-and-Spoke VPN behavior as defined inSection 4.3.5 of RFC 4364) in any way.


 


Regards, and lots of thanks in advance,


Sasha


 


Office: [phone]


Cell:      [phone]


Email:   [e-mail]


 


 



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